A major concern in the packaging of potentially harmful medication is the provision of container closures which provide acceptable seals and are childproof. Childproof closures are those which cannot be opened by young children and cannot be easily opened by older children.
A number of bottle closure structures have been introduced in recent years which employ various means of preventing a young child from easily opening the cap, but all of these childproof closures are subject to some criticism or fault.
One approach to a childproof closure is found in U.S. Pat. No. 4,106,651. This patent discloses a safety closure assembly in which a cap, threaded onto the neck of a container, is provided with a hinged flap having locking means which engage corresponding locking means formed on the container neck. The hinged flap is pivoted in a plane parallel to the plane of the container mouth such that engagement of the locking means prevents rotation of the cap thereby locking it in position on the container. This design is relatively expensive to manufacture and assemble since accurately aligned screw threads are required both on the container and cap to assure that the locking means on the cap aligns with the corresponding locking means on the container neck when the cap is fully tightened.
Another approach to a childproof closure is disclosed in U.S. Pat. No. Re. 29,793 which has a hinged cap adapted to close an opening in the top of a container. The cap is hinged to the closure and includes a locking flap engageable with an outwardly extending projection formed on a sidewall of the closure neck. The locking flap is pivoted in a plane perpendicular to the plane of the container mouth so as to prohibit upward motion and opening of the cap without first disengaging the locking flap from the projection. Such disengagement is accomplished by depressing the resilient cap against a center pivot, and because of the resiliency of the cap, thereby separating the flap from the projection on the container.
It is an object of the present invention to provide a childproof closure having an improved locking mechanism which is less subject to being opened by small children than the prior art.
It is a further object of the present invention to provide childproof closure which may be sealingly screwed onto a container.
It is still a further object of the present invention to provide a childproof closure which can be readily opened by an adult.
It is an even further object of the present invention to provide a childproof closure which can be readily opened by an adult without having to exert a physical effort or force, and which therefore, can be opened by an adult having an physical infirmity such as, for example, arthritis.